Charge level of the vehicle's battery at the start of the route (in kWh). It must be non-negative and less than or equal to the value of BatterySpecifications.totalCapacityInKilowattHours, otherwise the BatterySpecifications instance is considered invalid. Defaults to 0. Note: For a user-planned ChargingStop, this parameter is also required. If not set greater than 0, the route calculation will fail as an an invalid parameter error.